Converging evidence from across laboratories and approaches has documented the existence of shared neural representations for the perception and production of action (termed mirror neurons or the mirror neuron system, MNS) in adult nonhuman and human primates. Although it is widely hypothesized that the MNS supports the development of social perception and social responses, there is little direct investigation of these possibilities. The proposed experiments address this issue by investigating the potential role of the MNS in the development of two foundational social abilities: action anticipation, the ability to generate predictions about the outcomes of others' actions, and goal imitation, the ability to reproduce the meaningful components of others' actions. The first goal of the proposed research is to use behavioral methods to test the hypothesis that developing action production systems support infants' abilities to anticipate and imitate others' actions. To this end. Panel 1 develops eye-tracking measures of action anticipation and Panel 2 develops behavioral measures of goal imitation. Each panel will investigate relations between the focal ability and infants' own developing actions, as well as the effects of motor training and motor interference. In addition, drawing on insights from Project III, these studies will test whether infants' anticipatory and imitative responses are modulated by the contextual factors that modulate mirror neuron function in primates. The second goal of the proposed research is to implement these measures in studies that assess the neural processes that correlate with infants' action anticipation and goal imitation. The studies in Panel 3 pursue this goal by integrating the behavioral measures developed in Panels 1 and 2 with electroencephalogram (EEG) studies of mu rhythm suppression, a neural response that has been argued to reflect MNS activation. To achieve this goal, the studies will draw on methods developed in Projects I and IV. In addition to addressing these two primary research goals, the data from these experiments will be recruited to inform the development of computational models in Project IV.